Different devices have been provided to remove sediment which passes to the bottom of a liquid-containing vessel. Typically, these devices include a drive mechanism, at least portions of which are positioned exteriorly of the liquid contained in the vessel. The primary purpose for avoiding contact by the drive mechanism with the liquid is because the drive mechanism includes an electric motor and current conducting wires. It is a highly advisable safety feature to minimize the possibility of the liquid acting as a current conductor. For example, in U.S. Pat. No. 4,090,966 to Clendenen, a sediment collecting system is shown which includes an electric motor for use in driving wire cable about pulleys. The motor is positioned outwardly of the liquid contained in a basin. In addition, as again exemplified by the patent to Clendenen, previously known drive mechanisms include various gear and pulley arrangements. The drive mechanism of the present invention, on the other hand, is devoid of electric motors, current conducting wires, gears and pulleys. The drive mechanism herein described is placed within the liquid and supported by the floor of a vessel and is used to move a suction pipe or scraper in a step fashion to remove sediment.